This invention relates to a flow control assembly and more particularly, to such an assembly including a valve for controlling the flow of abrasive material.
Although there are a countless number of valves used to control the flow of fluids and materials, the number of valves available for controlling the flow of abrasive material is somewhat limited
The valves that have evolved for controlling the flow of abrasive material usually are in the form of a ball valve, or the like, which is turned from a first position in which it permits flow between the inlet and outlet conduits to a second position in which it prevents the flow. A seal is normally located in connection with the valve, usually at the downstream end thereof, which provides a seal between the ball valve surface and its housing. However, when the flow of abrasive material is being controlled and the valve is partially opened or closed, the seal is exposed to, and often damaged by, the abrasive material. Also, the valve surface itself is exposed to the material.
One suggested solution to this problem is to provide a seal at the upstream end of the ball valve so that the particulate material will pass through the seal. However, in this instance, the ball valve surface is still exposed to the abrasive material which can cause damage.